1. Field of the Invention
This disclosure relates to a single-input multi-output surface acoustic wave device.
2. Description of the Related Art
A surface acoustic wave (“SAW”) is not an electromagnetic wave, but rather is a pressure wave that is generated by the displacement of particles. This displacement of particles can be brought about by external factors, such as, for example, thermal, mechanical, and/or electrical forces. As a result, a majority of the vibrational energy in the SAW is concentrated on the surface of a medium. A SAW sensor is a device that senses the presence or properties of a target material using surface acoustic waves. Generally, the SAW sensor is disposed on a substrate that includes a piezoelectric material, and the SAW sensor includes a receptor that specifically binds to a target material. When a solution containing the target material flows to the SAW sensor, its wavelength is changed by a physical, chemical and electrical interactions between the target material and the receptor. Accordingly, the content of the target material can be detected and monitored by the change in the signal change caused by the change in the wavelength.
The SAW sensor is sensitive to changes in pressure of a fluid, and viscosity or density of a medium, as well as mass on the surface. Thus, it is very important to minimize any noise that could cause a change in the signal other than that caused by the sample that is to be detected.
In a typical SAW sensor, an oscillation technique of applying an output signal emitted from an output inter-digital transducer (“IDT”) of the SAW sensor to an input IDT of the SAW sensor is used to generate a surface acoustic wave in an electrode of the SAW sensor. Further, a technique of generating a certain frequency outside the SAW sensor includes applying the frequency to an input IDT, and plotting an emitted output signal output of the SAW sensor.